Regarding methods for producing optically active amines using transaminases, there are many reports concerning methods for producing α-amino acid, but there are few reports concerning methods for producing optically active amine compounds other than α-amino acid. In recent years, a transaminase that generates optically active amines other than α-amino acid has been discovered, and the use thereof for a general method for efficiently producing optically active amines is expected.
However, transaminases known to date for generation of optically active amines other than α-amino acid have had many problems (Non-patent Document 1).
For example, it is useful to enzymatically remove α-keto acid generated as a by-product by using α-amino acid as an amino group donor. However, α-amino acid that acts as an amino group donor is substantially limited to alanine, which is expensive and has low solubility.
Among optically active amino compounds other than α-amino acid, a transaminase that generates (S)-1-benzyl-3-aminopyrrolidine, that is, a particularly useful pharmaceutical intermediate with high optical purity of 93% e.e. or more, has remained undiscovered (Patent Documents 1 and 2 and Non-patent Document 2).